Mountain bikes and their individual parts such as frames, handlebars, stems or seat posts have to withstand high loads in tough off-road use. Many potential buyers are particularly sceptical about carbon as a material. So what about the durability of used mountain bikes? Are used parts safe? We asked the bicycle expert Dirk Zedler for you. He gives tips on what you should look out for in order to identify possible accident damage.
Topic overview:
Durability: Are used mountain bikes and parts safe?
Carbon is a wonderful material for bikes: stiff, light and affordable when used. But what about the safety of used components such as handlebars, seatposts or cranks?
The crux of the matter with carbon is that the material does not deform in the event of a fall or accident, even if it has already been overloaded. This makes it virtually impossible to judge from the outside. How the BIKE handlebar test (5/2014) has shown that there are very large differences in the durability and especially the crash tolerance of carbon. Used handlebars, seat posts and cranks therefore carry a high risk if you are not familiar with their history.
What can I look out for to minimise the risk, where is the limit for signs of use or age?
The ageing process of carbon is not an issue, it is the damaging events such as unsuccessful jumps or falls that are critical. Theoretically, previous damage can be seen in the handlebar grips, pedals or saddle, but these are often replaced before sale in order to achieve a better price. If you really want to be on the safe side, the only option is to replace the load-bearing components.
Carbon frames, whether fully or hardtail, certainly have the greatest second-hand savings potential, but are a completely different topic. How can I avoid buying a ticking time bomb?
Experience has shown that the all-clear can be given for most frames. Sudden complete failure is no longer an issue with well-made frames from leading manufacturers. The risk is also somewhat lower as the tubes support each other. Before buying, it is worth taking a critical look at the exposed components. If the seller does not present the pedals, grips and saddle or if they are suspiciously new, then I would advise against it. The condition of the wheels also says something about the previous life of the used bike. Another indicator is the paintwork. On a very clean frame, you can either see cracks in the critical areas or feel them with a soft cloth if you run it over the tubes.
Is it possible, for example, to have a frame professionally inspected for defects/deficiencies?
The much-cited X-ray, as well as other screening methods, do not lead to any real results. Manual carbon production inevitably leads to deviations in production, and it is practically impossible to distinguish non-critical manufacturing defects from possible damage. For a reliable statement, the new condition would have to be documented, but unfortunately this is never the case. A few manufacturers and also we at Zedler-Institut test carbon frames with an extended stiffness test procedure in the laboratory. However, this requires a lot of experience and equipment. Cost point: from 500 euros.
Beware of cost traps: Frame, suspension fork, shock absorber, bearings (headset, crank, rear triangle), drivetrain, gears, wheels, tyres
A bike consists of many moving parts that wear out. We show you the most common cost traps - so that the supposed bike bargain doesn't turn into a money pit after all.
Frame
Carefully inspect the frame for cracks, dents or scratches. While the use and possible defects of an aluminium frame can often be seen immediately, this can be much more difficult with carbon. It is essential to ask the seller about the previous history.
Suspension fork & damper
Compress and extend the suspension several times and push the wheel forwards and backwards with the brake applied. If bearing play is recognisable or oil is leaking, it is better to keep your hands off. A service alone can quickly add up to 75 to 100 euros per suspension element, and considerably more for repairs.
Bearings (headset, crank & rear triangle)
Replacing the headset, bottom bracket or rear bearings (between 50 and 125 euros) is annoying but usually associated with reasonable costs. To ensure that the frame is not damaged after all (e.g. if the bottom bracket is creaking), the defect should be included in the purchase contract or, ideally, repaired by the seller.
be repaired by the seller.
Drive & gearstick
Defects and wear are best recognised during a test ride. Ideally, a replaced chain is sufficient (from 25 euros). If the chainrings and sprockets are also due for replacement, it can be really expensive (from 150 euros). A bent derailleur hanger or kinked cables indicate more than just a worn derailleur.
Wheels & tyres
Lateral or radial runout can be found by turning the wheels in the frame. To check the hubs for smooth running and possible bearing play, the wheels should be removed. Replacing worn tyres is expensive: a good pair costs from 50 euros.
Part 2 from 2
Part 1: The path to the affordable dream bike
Part 2: How to avoid unnecessary costs and bad purchases
The article with further useful information was published in BIKE issue 06/2014. You can download the
Buy edition here or the Download article here as PDF
Would you like to buy a used mountain bike? Here you will find the most popular models in our Second hand model advice
